security/headscale: Update to 0.26.1

headscale 0.26.0 has breaking changes refer to the release notes for more
details.

Changes since 0.25.1

• https://github.com/juanfont/headscale/releases/tag/v0.26.1
• https://github.com/juanfont/headscale/releases/tag/v0.26.0

PR: 287061
Approved by: maintainer timeout, 2+ weeks